1. Field
The present invention relates to the field of image processing, and in particular to an apparatus and a method for detecting a color checker in an image.
2. Description of the Related Art
Recently, a color checker introduced by X-rite Company becomes more and more popular, which may be used for correcting a color of a photo captured by a camera. As shown in FIG. 1, the color checker includes 24 colored squares of standard colors. In capturing, a color checker may be placed together with a scenario or an object to be captured. And color correction may be performed on the photo according to colors of the color checker in the photo after capturing. However, as a location, a size and rotation of the color checker in the photo are random, a position area of the color checker must be marked manually, and then the color correction is performed.
In order to achieve an automatic color correction function, some researchers propose methods for automatically detecting a color checker in a photo.
In a method in document 1, a modified SIFT (scale invariant feature transform) feature is used for detection of a color checker. However, as dimensions of its feature vector reach 384, the method is made time consuming. Furthermore, a rough position of the color checker is only given in this method, but positions of each colored square are not given.
Document 2 proposed a detection method based on a hue H (HSV (hue saturation value) color space), in which structures of pyramid levels of images are used to speed up operations. However, in using such a method, when there is relatively large deviation, such as improper white balance setting in capturing, this method may be failed.
Document 1: S. Bianco, C. Cusano. Color Target Localization under Varying Illumination Conditions. Proc. Computational Color Imaging Workshop (CCIW'11), 2011; and
Document 2: A. Minagawa, Y. Katsuyama, H. Takebe, Y. Hotta, A color chart detection method for automatic color correction. Proc. International Conference on Pattern Recognition (ICPR), 2012.
It should be noted that the above description of the background art is merely provided for clear and complete explanation of the present application and for easy understanding by those skilled in the art. And it should not be understood that the above technical solution is known to those skilled in the art as it is described in the background of the present application.